Center of a cluster of latitude and longitude points in Google map android -
i trying center of shape in android. shape draw hand on map. have of co-ordinates mean values turning out trickier thought. want plot marker on mean latitude , longitude.
i have tried summing latitude , longitude separately , dividing number of points. not give correct answer. marker seems trailing behind draw figure. have tried using implementation gives same answer, previous question, calculate center point of multiple latitude/longitude coordinate pairs
the code have been using:
private void calculatefreehandpolygonparameters(){ double xvalues = 0; double yvalues = 0; double zvalues = 0; int count = 0; // linesforpolygon list of lines in polygon for(polyline line : linesforpolygon){ (latlng point : line.getpoints()) { xvalues += math.cos(math.toradians(point.latitude)) * math.cos(math.toradians(point.longitude)); yvalues += math.cos(math.toradians(point.latitude)) * math.sin(math.toradians(point.longitude)); zvalues += math.sin(math.toradians(point.latitude)); count++; } } double meanx = xvalues/count; double meany = yvalues/count; double meanz = zvalues/count; double centrallongitude = math.atan2(meany, meanx); double centralsquareroot = math.sqrt(math.pow(meanx, 2) + math.pow(meanx, 2) + math.pow(meanx, 2)); double centrallatitude = math.atan2(meanz, centralsquareroot); double latitude = math.todegrees(centrallatitude); double longitude = math.todegrees(centrallongitude); log.i("maps", "freehand parameters: x mean -> " + latitude + " y mean -> " + longitude); testmarker = mmap.addmarker(new markeroptions() .position(new latlng(latitude, longitude)) .title("polygon center") .snippet("lat: " + latitude + " long: " + longitude)); }
here centroid code:
public class polygoncentroid { private list<geopoint> points; private int pointssize; public polygoncentroid(list<geopoint> points) { this.points = points; this.pointssize = points.size(); } protected double polygonarea() { double area = 0; (int = 0, j; < pointssize; i++) { j = (i + 1) % pointssize; area += points.get(i).getlongitude() * points.get(j).getlatitude(); area -= points.get(i).getlatitude() * points.get(j).getlongitude(); } area /= 2.0; return area; } public geopoint centroid() { double cx = 0, cy = 0; double factor; (int = 0, j; < pointssize; i++) { j = (i + 1) % pointssize; factor = (points.get(i).getlongitude() * points.get(j).getlatitude() - points.get(j).getlongitude() * points.get(i).getlatitude()); cx += (points.get(i).getlongitude() + points.get(j).getlongitude()) * factor; cy += (points.get(i).getlatitude() + points.get(j).getlatitude()) * factor; } double = polygonarea(); factor = 1.0 / (6.0 * a); cx *= factor; cy *= factor; return new geopoint(cy, cx); } } 
also, please pay attention centroid can outside of polygon:
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